Organochlorine residues in human-milk have been reported in literature extensively, but relatively fewer publications exist on PCBs. No such reports have been made from the state of Louisiana, especially for the low-income residents liable to be exposed to such contaminants. The potential threats of organochlorine compounds to human health have been documented repeatedly, which occur as a consequence of biological magnification. The principal objective of this proposal is to estimate the extent of pesticide contamination to low-income residents as revealed by milk residues compared with high-income individuals. The maximum possible number of milk samples from nursing mothers of delta parishes and relatively pesticide-free parishes will be analyzed gas-chromatographically. The samples at the beginning and end of each feeding period will be analyzed separately. They will be collected from the same location throughout the investigation period. This will insure the validity of data in pooling. A large body of information concerning the donor's exposure to pesticides will be gathered by questionnaires and personal interviews, whenever possible. Special attention will be given to accuracy in quantitation and confirmation of pesticides, and to procedures differentiating Mirex and PCBs residues which are often confused. To maintain consistency all standards will be obtained from the Perrine Primate & Pesticide Effects Laboratory, Perrine, Florida. To avoid mistakes in calculations, a computerized gas-chromatography analyzer will be used. Thin-layer chromatography will also be done for confirmatory purposes. Further confirmation will be done by using different columns having different retention properties.